Context: girl and me have drinks in a bar. Girl gets drunk, wants to go home on her own (one of her whims). Outside, she can hardly stand, manages to hail a car. She gets in, car drives away. I feel uneasy.

My transation: She was too drunk for me to feel easy about (as she waved down a car)

Do you want to keep the structure of the sentence (she was too... for me...), because it is a little awkward. Also, depending to who you say that to, you may need to explain that concept of частник (gypsy cab), because if you just say "hail a car", most people think it was a taxi.

Here is my option:
As she hailed/flagged down a car /a gypsy cab, I felt uneasy because she was too drunk
As she hailed/flagged down a car /a gypsy cab, I felt she was unsafe because she was too drunk
As she hailed/flagged down a car /a gypsy cab, I was concerned for her safety because she was too drunk

Thank you for the question and let me assist you in translation of your text from Russian into English.
Она была слишком пьяна, чтобы я мог чувствоватьсебя спокойно за нее. -The thought of her being so drunk doesn't settle well with me.

-I was drinking with my girlfriend in the bar. At some point she decided to go home all alone (on her own) by taking a taxicab. She was a sloppy drunk hailing a gypsy (illegal) cab. As she climbed into the car and the vehicle took off with her, I became worried about her safety.

Hi! Sameer, you ignored my first suggestion like "the thought of her being so drunk doesn't settle well with me", probably, because you found it too broad and general. My second try I designed by increasing details especially for this specific situation. At this time my try is "this girl was incredibly intoxicated and I couldn't stay calm, because I continuously worried about her" or "this girl seemed too drunk to me and I was really stressed out about what could happen to her"
If you want to put exactly the opposite meaning in this wording then you can do it by saying "she was too drunk for me to feel easy about " or "she was too drunk for me not to worry about her" The guy, actually, doesn't care about her condition, because she is a grown woman and she knew what she is doing.
Remarkable answers were provided by Rusita.
Unfortunately, the first two answers from Zambala are not going to work, because it does sound as if the girl lost her reputation in his eyes. "She was too drunk and I could not feel good thinking about her" and "she was too drunk so I could not feel good thinking about her."
The third answer like "she was too drunk so I could not be at peace of mind about her" is incorrect due to incomplete thoughts. It's better to say something like "she was too drunk so I couldn't experience a state of peace of mind about what could happen to her"
Good luck in your translation. I did everything that I possibly can for you. With best regards Hope nobody will be mad at me for my pertinent remarks.
P.S. In the USA the most used slang for heavy drunk people are: lovely drunk (when someone is drunk and happy), angry drunk (gets ready for the fight), sloppy drunk and skunky drunk (no comments).

This is a little surprise. But I think I know what's really going on here. The confusion is caused by the second part of this Russian sentence "чтобы я чувствовал себя спокойно". The literal translation is deviating from original interpretation.

This is a little surprise. But I think I know what's really going on here. The confusion is caused by the second part of this Russian sentence "чтобы я чувствовал себя спокойно". The literal translation is deviating from original interpretation.

Click to expand...

In fact, this is an incorrect Russian sentence. You cannot "чувствовать себя спокойно" за кого-либо. This expression could be used only buy itself, without any additions. You can only say "(не) волноваться за кого-либо". For example: "она была слишком пьяна, чтобы я мог не волноваться за нее".

Nice catch and explanation, Lotto74. I was thinking that I would have used волноваться, but since I am not a native speaker of Russian I hesitate not only to correct but sometimes even to question someone else's usage in Russian.